Developer tank guide wall structure



Dec. 27, 1966 J. TAIN]! DEVELOPER TANK GUIDE WALL STRUCTURE 2 Sheets-Sheet 1 Filed March 12, 1964 United States Patent 3,294,003 DEVELOPER TANK GUIDE WALL STRUCTURE John Taini, Skokie, Ill., assignor, by mesne assignments, to Bell & Howell Company, Chicago, 11]., a corporation of Illinois Filed Mar. 12, 1964, Ser. No. 351,440 6 Claims. (CI. 9594) This invention relates to a developer tank arrangement for high speed gas contact development of radiant energy sensitive paper, one such typical example being a diazo type print, and more particularly, the invention is concerned with a guide wall structure for the open face of a chambered developer tank for developing, with full definition, the radiant energy sensitive paper carried across such face by a high speed endless belt type sealing sleeve that is maintained in a pressure sealing relation against the tank during movement across such face.

More specifically, this invention provides an improvement over the guide wall structure disclosed in the Taini application, now Patent No. 2,625,865. High speed photoprinting applications are limited by the development phase because as the speed is increased there is insufficient time allowed for achieving moisture and developer action on the print paper through developer gas contacting the paper. When handling larger size negative originals in a single side contact developer arrangement in a high speed operation, it is desirable to expose and develop a continuous web of copy paper. Heretofore, this desired operation could not be obtained at speeds appreciably higher than 40 feet per minute without causing objectionable streaking in the final prints. With a structure such as is shown in the Taini patent, streaking in the final print occurs along lines coincident with the guide wheels 19 and 20, and this effect becomes increasingly noticeable at speeds above 40 feet per minute in the case of largesized negatives. However, with the present invention, development at speeds as high as 75 feet per minute has been sustained without producing any noticeable streaking.

It is believed that streaking results from at least two conditions. The crowded arrangement either of roller wheels or of equivalent structures provides a bafiling effect restricting the freedom of developer gas flow and ultimately limits the quantity or concentration of gas that may actually contact portions of the print paper during the time of its travel across the open face of the developer. Secondly, the higher speed operation normally involves increased pressures acting between the moving sleeve and the guide wall structure and this may involve particularly severe pressure concentrations where crowned guide wheels or equivalent narrow contact surface conditions are encountered. Such pressure concentrations may exceed the stress limits of the coated print paper causing wrinkling and puckering of the sheet or cracking or compacting of the coating, thereby impairing its normal ability to absorb moisture and precluding effective high speed development.

This pressure concentration factor has been demonstrated in the case ofthe aforesaid Taini patent structure by removing intermediate rows of wheels until there remained two rows of intermeshing guide wheels at the lower end, two rows at the center, and two rows at the upper end of the guide wall structure. Experience with this modified structure showed that streaking of the print at the regions that contact the wheels remained a problem at high speeds.

The principal object of this invention is to provide a developer arrangement characterized by the provision of large size gas contact pocket regions spanning the open face and being free of intermediate print contacting sur- 3,294,563 Patented Dec. 27, 1966 faces and of intermediate flow restricting baffle structures.

Another object of the invention is the provision of a simple and less expensive developer tank arrangement which is nevertheless capable of developing a continuous web of printing paper at higher speed than has heretofore been possible.

Another object of the invention is the provision of a developer arrangement wherein such gas contact pocket regions are bordered and defined by wide faced rollers that constitute the only print contacting surfaces and that are disposed adjacent the entry and exit regions of the open face for extensive transverse contact with the print paper and consequent uniform pressure distribution.

A further object of the invention is the provision of a developer arrangement of this type and wherein a separate gas feed is provided to supply gas directly towards the print paper as it passes each contact pocket region thereof.

Still a further object of the invention is the provision of a developer arrangement of the above type and wherein the spacing between successive rows of rollers is several times as great as the roller diameter.

Another object of the invention is the provision of a developer tank of the above type and wherein each row of rollers is comprised of a plurality of elongated cylindrical roller elements in axial alignment and end-to-end adjacency and equipped with tubular end bearings supported on a common axle that is stablized at intermediate points by bridging structure that is spaced across the face and recessed inwardly from the print path to maintain substantially fully open lateral communication along the width of each gas pocket region.

Kunstadter Patent No. 2,200,451 shows a related developer tank arrangement, but it does not meet the present inventions objective of providing high speed development of diazo paper exposed through large size negatives for the important reasons that the pocket regions between successive rollers are spanned by rods D extending lengthwise of the print movement direction at a location to establish continuous contact with the moving print paper and for the additional reason that the entry and exit rollers are masked by the adjacent edges of the tank wall structure and are unable to distribute sleeve pressure resulting in pressure concentrations against the rods D.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same:

FIG. 1 is a side elevational view, partly in section, of a developer tank arrangement incorporating the invention;

FIG. 2 is a reduced face view of the developer tank guide wall structure; and

FIG. 3 is an enlarged fragmentary lengthwise section illustrating roller construction and mounting details.

Referring now to the drawings, the developer tank is designated generally at 10 in FIG. 1 and it comprises a casing having side walls 108, a rear wall 10R, an angled base wall 10B, all defining a developer gas chamber C having substantially full span communication with an enlarged open face provided on the front of the casing in facing relation to a high speed endless belt type sealing sleeve 11. The casing has marginal side portions 10M (FIGS. 1 and 2) bordering and defining the lateral extremities of its open face and engageable by marginal regions of the sleeve 11 in relatively slidable sealing contact therewith to prevent escape of gas through the open face of the gas chamber C. The marginal side portions 10M have a smoothly curving, generally convex outline configuration and the sleeve 11 is engaged over a set of upper and lower rollers, 12U and 12L respectively, arranged at locations to cause the sleeve to conform to the outline configuration of the exposed face of the casing and to ride with positive pressure thereagainst to define a print path of the same general outline configuration. A roller or series of axially spaced friction rollers 12F having a frictional surface material, e.g., rubber, may be disposed adjacent the sleeve 11 and biased toward the lower roller 12L to increase frictional contact between the sleeve fl and the lower roller 12L and prevent slippage therebetween.

A guide wall structure 13 for the open face of the casing is mounted to the casing and includes lengthwise spaced rows ML, 141 and MU of idler rollers 15 spanning such face transversely. The rollers 15 of these rows preferably have their peripheries substantially tangent to the outline configuration established by the marginal side portions of the casing to enable these rollers to supplement the side portions 10M in bearing the applied sleeve pressures. The convex form of the print path results in substantial applied sleeve pressure as is desirable for achieving effective edge sealing the developer gas chamber.

The rollers have a row spacing in the direction of the print path that is several times as great as the roller diameter and there is defined between each adjacent set of rows a gas contact pocket region P extending full span transversely of the open face of the casing.

The casing has an inlet guide apron 16 bordering the print entry region of its exposed face and forming a smoothly curving guide surface between the lower drive roller 12L, and the exposed face of the casing. At the top of the casing, an inturned flange ll7 borders the print exit region of the exposed face and presents a smooth ramp surface that avoids any possibility of fouling of either the sleeve or the print paper at this point.

The developer fluid for the tank arrangement illustrated herein preferably comprises a mixture of ammonia gas and water vapor. The ammonia is introduced directly as a gas through separate dispersion pipes 18 and 19 provided for each pocket region at the exposed face of the casing. Each of these pipes extends substantially full width between the casing side walls and is provided with outlet openings at spaced points therealong for discharging ammonia gas along paths leading directly into and through the contact pocket regions. The lower gas pipe 18 is directed towards the pocket region P defined between the lower and intermediate rows ML and MI of rollers, and the upper gas pipe 19 is directed into the contact pocket region between the intermediate and upper rows 141 and 14U of rollers.

Water vapor is generated adjacent each gas supply pipe and for this purpose lower and upper vaporizing trays 20 and 21, respectively, span the casing with a single water feed pipe 22 being provided above the upper vaporizing tray 21 which is provided with a drain pipe 21D to supply water to the lower tray 20. Each of the water vaporizing trays 2t), 21 is horizontally disposed in order that the greatest surface area be exposed and, consequently produce a high moisture vapor atmosphere for improved development. A 200 watt heater rod 21H underlies the upper tray 21, and a 1400 watt heater rod 20H underlies the lower tray 2t) to vaporize the water at the desired rates. The water is preferably introduced by a pump operating in timed relation to the sleeve drive (not shown).

As best seen in FIG. 3, each of the rows 12L, 121 and 12U comprises a set of four aligned rollers 15 each equipped with tubular end insets 24 fixed therein and constituting end bearings journalled on a common axle 25 that is supported at intermediate points on bridge plates 26 that span the open face of the casing in the print movement direction.

In the illustrated embodiment each roller 15 is comprised of about a 10 inch length of stainless steel tubing 115T of Vs inch O.D. and provided with a inch surface coating llSC of Teflon or equivalent lubric plastic material. to provide an overall roller diameter of 1 inch. The

insert bearings 24- may be of glass-filled Teflon or equivalent lubric plastic material and each bearing has an axleengaging cylindrical interior face 24C and a bridge plate engaging annular end face 24A acting as low friction bearing surfaces. The axle 25 extends through a retaining hole provided in each bridge plate 26 and is held by a snap ring 25R and threaded nut 25N.

Each of the bridge plates 26 is recessed a sufficient clearance distance inwardly of the outline configuration of the print path to avoid acting as a baffle tending to interrupt substantially free lateral flow along each of the pocket regions P. The recessed bridge plate arrangement thus encourages full surface contact of the print paper by the gas enriched developer medium.

At their ends, the bridge plates 26 are fixed to upper and lower anchor brackets 27 provided within the casing. The recessed intermediate regions of the bridge plates 26 have perforated deflector plate structure 28 fixed thereon and extending the full width of the exposed face for preventing any possibility of misdirected paper falling into the developer tank. Since the deflector structure 28 is not a primary load bearing element, it may be perforated as liberally as desired to ensure easy communication of the ammonia gas streams with the pocket regions adjacent the print path. Actually, as the print paper takes up moisture, its tendency is to curl toward the sleeve 11 and this minimizes any contact between the paper and the perforated deflector plate structure 28. Any other form of recessed deflector structure may be employed for a similar purpose so long as it does not set up a baffling effect that may tend to limit free lateral flow along the pocket regions P and so long as it does not present structure intermediately of the pocket regions and capable of contacting the print paper.

While a preferred embodiment of the invention has been illustrated herein, it is to be understood that changes and variations may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

What is claimed is:

1. A developer tank for high speed gas contact development of radiant energy sensitive paper carried thereaeross in pressure contact therewith by a high speed endless belt type sealing sleeve and comprising a casing providing a gas chamber, means for producing print developing gas in said chamber, said casing having marginal side portions bordering and defining an enlarged open face for said chamber and relatively slideably engageable by marginal regions of the sleeve to establish edge seals preventing escape of gas through said open face, said marginal side portions having a prescribed outline configuration in the direction of lengthwise movement of said sleeve to facilitate full length pressure contact with said sleeve during high speed movement thereof, and guide wall structure mounted to said casing and having a plurality of separate rows of idler rollers of transversely elongated configuration spanning said open face between said marginal side portions and constituting the sole print contacting surfaces of said guide wall structure to define a separate gas contact pocket region between each set of adjacent rows and extending full size across said face for unimpeded lateral flow of developing gas, said rows of rollers including an infeed row spanning said open face at a location therein adjacent its print entry region and an outfeed row spanning said open face at a location therein adjacent its print exit region, with the rollers of said rows having peripheries substantially tangent to the outline configuration established by said side portions and having a row spacing several times as great as the roller diameter.

2. A developer tank in accordance with claim 1 and wherein each row of rollers comprises a plurality of elongated tubular rollers, said rollers having a length dimension several times as great as their diameter, a plurality of bridge elements spanning said open face in the lengthwise direction of the print path and at a location set inwardly of the print path to enable free lateral flow along each said pocket region, a common axle extending through the rollers of each row and supported at its ends and at points thereof intermediate adjacent rollers on bridging elements spanning said face in the direction of said print path, and tubular end bearings fixed within each roller and journalled on the corresponding axle to present a cylindrical internal bearing face engaging the axle and an annular end face engaging the adjacent bridge element.

3. A developer tank in accordance with claim 2 and wherein deflector structure in the form of perforated plate elements is fixed to said bridge elements to span each of said pocket regions at a location set inwardly of and free of contact with paper moving along said print path.

4. A developer tank for high speed gas contact development of light sensitive paper carried thereacross in pressure contact therewith by a high speed endless belt type sealing sleeve and comprising a casing providing a gas chamber, said casing having marginal side portions bordering and defining an enlarged open face for said chamber and relatively slidably engageable by marginal regions of the sleeve to establish gas retaining edge seals along opposite sides of said open face, said marginal side portions having a prescribed outline configuration in the direction of lengthwise movement of said sleeve to facilitate full length pressure contact with said sleeve during high speed movement thereof, and thereby define a correspondingly shaped print path and guide wall structure mounted to said casing and having a plurality of separate rows of idler rollers of transversely elongated configuration spanning said open face between said marginal side portions and constituting the sole print contacting surfaces of said guide wall structure to define a separate gas contact pocket region between each set of adjacent rows and extending full size across said face, said separate rows of rollers including an infeed row spanning said open face at a location therein adjacent its print entry region, an outfeed row spanning said open face at a location therein adjacent its print exit region and an intermediate row spanning said open face at a location intermediately of said infeed and outfeed rows, with the rollers of said rows having peripheries substantially tangent to the outline configuration established by said side portions, a first gas inlet pipe spanning said chamber transversely to lie cross-wise of said print path and having spaced openings directed towards one of said pocket regions, a second gas inlet pipe spanning said chamber transversely to lie crosswise of said print path and having spaced openings directed towards another of said pocket regions, and horizontal tray means beneath each of said pipes for producing water vapor for mixture with gas discharging therefrom.

5. Guide wall structure for an open face of a chambered tank utilized for high speed gas contact development of radiant energy sensitive paper carried in pressure contact across said face by a high speed endless belt type sealing sleeve arranged to react in sealing relation against the tank during movement thereacross to establish therebetween a print path having a prescribed smoothly curving generally convex outline configuration in the lengthwise direction of movement of said sleeve, said guide wall structure having a plurality of bridge elements spanning said open face in the lengthwise direction of the print path and describing a contour set inwardly of the print path, a plurality of separate rows of idler rollers spanning said open face transversely and rotatably supported in end-to-end adjacent axial alignment by said bridge elements, with the rollers of said rows having peripheries substantially tangent to the print path and constituting the sole print contacting surfaces throughout the region of said face, said rows including an infeed row spanning said open face at a location therein adjacent its print entry region and an outfeed row spanning said open face at a location therein adjacent its print exit region, with adjacent ones of said rows being spaced apart lengthwise of said print path a distance several times as great as the diameter of said rollers to define therebetween a gas contact pocket region exposed directly to a print moving across said face and extending full size transversely of said face for unimpeded lateral flow of developing gas, and with said rollers having a length several times as great as said diameter.

6. Guide wall structure in accordance with claim 5 and wherein deflector structure in the form of perforated plate elements is fixed to said bridge elements to span said pocket regions at a location set inwardly of said print path.

References Cited by the Examiner UNITED STATES PATENTS 2,625,865 1/1953 Taini -89 2,933,997 4/1960 Trump 95-94 3,208,367 9/1965 Aizawa 95-89 FOREIGN PATENTS 664,373 8/1938 Germany.

NORTON ANSHER, Primary Examiner. CLIFFORD B. PRICE, Examiner. 

1. A DEVELOPER TANK FOR HIGH SPEED GAS CONTACT DEVELOPEMENT OF RADIANT ENERGY SENSITIVE PAPER CARRIED THEREACROSS IN PRESSURE CONTACT THEREWITH BY A HIGH SPEED ENDLESS BELT TYPE SEALING SLEEVE AND COMPRISING A CASING PROVIDING A GAS CHAMBER, MEANS FOR PRODUCING PRINT DEVELOPING GAS IN SAID CHAMBER, SAID CASING HAVING MARGINAL SIDE PORTIONS BORDERING AND DEFINING AN ENLARGED OPEN FACE FOR SAID CHAMBER AND RELATIVELY SLIDEABLY ENGAGEABLE BY MARGINAL REGIONS OF THE SLEEVE TO ESTABLISH EDGE SEALS PREVENTING ESCAPE OF GAS THROUGH SAID OPEN FACE, SAID MARGINAL SIDE PORTION HAVING A PRESCRIBED OUTLINE CONFIGURATION IN THE DIRECTION OF LENGTHWISE MOVEMENT OF SAID SLEEVE TO FACILITATE FULL LENGTH PRESSURE CONTACT WITH SAID SLEEVE DURING HIGH SPEED MOVEMENT THEREOF, AND GUIDE WALL STRUCTURE MOUNTED TO SAID CASING AND HAVING A PLURALITY OF SEPARATE ROWS OF IDLER ROLLERS OF TRANSVERSELY ELONGATED CONFIGURATION SPANNING SAID OPEN FACE BETWEEN SAID MARGINAL SIDE PORTIONS AND CONSTITUTING THE SOLE PRINT CONTACTING SURFACES OF SAID GUIDE WALL STRUCTURE TO DEFINE A SEPARATE GAS CONTACT POCKET REGION BETWEEN EACH SET OF ADJACENT ROWS AND EXTENDING FULL SIZE ACROSS SAID FACE FOR UNIMPEDED LATERAL FLOW OF DEVELOPING GAS, SAID ROWS OF ROLLERS INCLUDING AN INFEED ROW SPANNING SAID OPEN FACE AT A LOCATION THEREIN ADJACENT ITS PRINT ENTRY REGION AND AN OUTFEED ROW SPANNING SAID OPEN FACE AT A LOCATION THEREIN ADJACENT ITS PRINT EXIT REGION, WITH THE ROLLERS OF SAID ROWS HAVING PERIPHERIES SUBSTANTIALLY TANGENT TO THE OUTLINE CONFIGURATION ESTABLISHED BY SAID SIDE PORTIONS AND HAVING A ROW SPACING SEVERAL TIMES AS GREAT AS THE ROLLER DIAMETER. 